As mobile electronic devices such as smartphones continue to become more common, the capabilities of such devices continues to grow. However, the resources of mobile devices—display area, storage capacity, computational power and the like—remain limited in comparison with their mains-powered desktop counterparts. The limitations of mobile devices become apparent in various areas, including mobile devices' handling of email messages.
Some email accounts are organized on mail servers in folder structures: each email is assigned to a folder in the mail server, whether a default folder or other, non-default folders, according to rules. Assigning an email to a non-default folder can result in the message being partially hidden when the email account is viewed on a desktop computer with a large display. For example, rather than the sender and subject of the email being visible, only an indication that a new message has been received may be provided. However, some mobile devices do not implement the folder structures locally in order to conserve resources, and cannot display partially hidden messages, instead hiding such messages entirely due to their reduced display areas.
To remedy the above issues, in some email systems, an intermediate server between the mail server and the mobile device examines an email and marks the email as being “filed” when the email has been assigned to a non-default folder on the mail server, and “unfiled” otherwise. The marking can be done with a flag having two states. The mobile device is then configured to examine the flag as received from the intermediate server, and to display messages that are marked “unfiled”, as well as unread messages that are marked “filed”.